'78 decoded?

first of all hi i'm new :)

second i just got my hands on my first elky and i'm starting to put money into it. did some searching around for vin info and this is what i've found

my vin = 1W80U8D52584
POSITION 1 (DIVISION IDENTIFICATION) = (1)CHEVY
POSITION 2 (VEHICLE SERIES) = (W)EL CAMINO
POSITIONS 3&4 (MODEL) = (80)EL CAMINO
POSITION 5 (ENGINE CODE) = ? (U)402? 396? 305?
POSITION 6 (MODEL YEAR) = (8)1978
POSITION 7 (ASSEMBLY PLANT) = (D)DORAVILLE
POSITION 8 (ENGINE?) = ? (5)

i've found 3 different conflicting sites on the internet for position 5, and was wondering if someone could help clear it up for me, i havn't gone thru and figured out what all is stock on it yet but it currently has a 350 :) and as for position 8 isn't that where it starts the production number?

any help is appreciated

What I find is that the fifth digit identifies the engine. "U" equal a V8 - option LG3, carb is a 2BC, and the CID is 305. Trans could be M20, M29, or M38.
Your correct on the 6th and 7th digit.

The last six digits represent the production number.

Hope it helps.

very cool thanks :) so this rolled off the line with a 305 eh? i thought the whole thing was stock when i bought it :/ whatever, should be fun :)